"We are off to a really bad start in 2014," Dr. Gil Chavez, state epidemiologist with the California Department of Public Health, said during a phone call with reporters Friday.
Chavez delivered his comments as the health department released a report summarizing the latest data on this year's epidemic of pertussis, or whooping cough. Of this year's cases thus far, 3,614, or 84%, have occurred in patients 18 or younger. Out of 142 illnesses that required hospitalization, 89, or 63%, were in infants 4 months or younger.
Three babies have died from pertussis infections in 2014, Chavez said, although two of those will be attributed to 2013's case count because they initially became ill last year.
Because infants less than a year old are at the highest risk of hospitalization and death from pertussis — and because babies generally do not receive pertussis vaccinations until they are 8 weeks old — Chavez said that all pregnant women should receive the Tdap vaccine during their third trimester.
"Vaccination of pregnant women is the most important thing that can be done to protect infants," he said, because the mothers' antibodies can be passed along to their newborns.
Whooping cough cases peak on a three- to five-year cycle. Based on historical patterns, Chavez said, it is likely that disease activity will remain high through the summer. But he said it was too soon to know if this year would be worse than 2010, the last year pertussis peaked.
That year, more than 9,000 Californians contracted the disease.